This invention is an improved windshield washer/wiper apparatus for a motor vehicle of the type which is activated to apply cleaning fluid to the windshield and move a wiper across the windshield in a repeating wipe pattern in response to a washer switch and further activated to continue to move the wiper through several additional wipe cycles after cessation of cleaning fluid application to clear the cleaning fluid from the windshield and stop the wiper in a predetermined park position at the end of the last wipe cycle.
Windshield washer/wiper apparatus of the prior art is known in which an electric washer apparatus is activatable by a washer switch to apply a cleaning fluid to the windshield and an electric wiper drive apparatus is activatable by the washer switch to drive a wiper across a vehicle windshield in a repeating wiper pattern. A wiper position responsive switch is activated by the wiper drive apparatus to open only through a predetermined wipe angle of the wiper within the wipe pattern and close through out the remainder of the wipe pattern. The electric wiper drive apparatus is responsive to the position responsive switch to continue driving the wiper through the wipe pattern while the position responsive switch is closed and, when not otherwise activated, to deactivate and park the wiper in a predetermined park position within the predetermined wipe angle when the position responsive switch opens.
The additional cycles may be provided by charge storage means such as a capacitor charged to a first predetermined voltage when the electric washer apparatus is activated and thereafter allowed to slowly discharge through a resistance while maintaining the electric wiper drive apparatus activated until a lower, second predetermined voltage is reached. As long as the position responsive switch is closed at that point, the cycle will be completed until the position responsive switch opens, deactivates the electric wiper drive means and parks the wiper in the predetermined park position.
However, the voltage on the capacitor in the prior art apparatus may reach the second predetermined voltage while the wiper is in the predetermined wipe angle and the position responsive switch is thus open. If this is the case, the wiper may be parked at a different position within the predetermined wipe angle from the desired predetermined park position, since the position at which the wiper is parked will not be controlled by the opening of the position responsive switch. The resulting occasional inconsistency in wiper parking may be noticeable to the vehicle driver and/or others.